The study analyzed how changes in precipitation affect runoff in the Yellow River region. They found that while precipitation levels remained relatively stable, runoff decreased significantly. This decrease was most pronounced in the Huangfuchuan watershed. The researchers identified abrupt changes in runoff patterns in the Hekou-Longmen and Huangfuchuan watersheds. The study also calculated the impact of precipitation on runoff reduction, showing that precipitation played a significant role in the decrease of runoff in all three study areas.